Datsun Roadster Forum-311s.org

I would like to get advice for the roadster. Looking online there is much general and model specific info. I can do a search on here and get info here and there. Would like to have all of this in one thread.

I plan to put a bung in immediately after the header. I don't really want to install a gauge so want recommendations for a handheld reader. The info I scan over doesn't seem to tell you about doing a static test in the driveway or the need to drive the car. So here we go gurus, bring it forth with nice concise answers or a bulleted list if possible.

I definitely have interest in this knowledge also.

I made a setup decades ago. I welded a bung onto a 2’ length of talepipe that fit into my megaphone exhaust tip. I used bungee cords to hold it in place. I screwed a Nissan wide band powered sensor in & wired it to a voltmeter. Seemed to work well but I had to look up the ratio. There are now cheap O2 gauges so I will probably buy one soon. My car is off the road now & I’ll also probably weld the bung into the new exhaust.

Peace ,
Pat
Pat

I did the "extension on the tailpipe" thing also. I used the standard narrow band sensor read by a volt meter so it basically said rich or lean.

keith0alan wrote: Wed Oct 26, 2022 2:58 pm I did the "extension on the tailpipe" thing also. I used the standard narrow band sensor read by a volt meter so it basically said rich or lean.

I have no idea how you would use a voltmeter for this. Most info says put the sensor up front. What quality of reading do you get at back?

As above I'm looking for info on these two things.

Recommendations for a handheld reader.

Static test in the driveway or the need to drive the car or both.

Irrelephant

Daryl Smith wrote: Wed Oct 26, 2022 4:21 pm Ideally you would want to test both idle and driving. Tho not sure what your options would be to tune for driving conditions with the carbs....If SU's you could try different needles, but, that testing may have been done, and you could get a needle recommendation from someone here that would be suitable, then adjust to get the best compromise between driving and idle?

As far as handheld reader, I have no experience, just in dash gauge/controller from Innovate.

Thanks. Tried two richer needles from Keith and it did not solve the problem.

Curtis wrote: Wed Oct 26, 2022 3:19 pm

keith0alan wrote: Wed Oct 26, 2022 2:58 pm I did the "extension on the tailpipe" thing also. I used the standard narrow band sensor read by a volt meter so it basically said rich or lean.

I have no idea how you would use a voltmeter for this. Most info says put the sensor up front. What quality of reading do you get at back?

I used the O2 sensor with the built in heater. Run 12 volts to the heater and read the sensor with a digital volt meter. Below .5 volts is lean and above .5 volts is rich. Without the built in heater it will not work at the end of the tail pipe. It seems to work quite well. With two carbs there can be problems. If one carb is rich and the other lean it obviously will have problems. I used the colortune to get them balanced. Once the carbs are matched then the O2 sensor is much more useful. Nothing is a perfect answer. Different tools give you different bits of information to help you understand what the carbs are doing.

Can't recommend the Innovate highly enough.
Used it on my '65 SP310 when I got it on the road and was invaluable to fine tune the AFR.
Spark plugs reflected the state of tune with their colour so all was good

Todays O2 senors read 10-20 X per second ( its a on-off-on,off,on,off,on,off)and in the 50 mil amp range
Plus the tip needs to be in the flow of the gas stream the inside of the porace porcelain cup
Has the platinum that read more or less oxygen. Realize you have vacuum in the exhaust stream too this is why the computer needs to makes sense of the readings
A EGT sensor can tell the carb ratio , be cool to have the rich to lean knob ajustors cable gears on the needles like aircraft

I plan to use a wideband with gauge in my car. There are tons of options out there. Prices can range, but RaceTronix has an all inclusive kit for $150. Everything included, and you always know what is happening. The tough part is gauge placement, but there a ton of gauge styles. Pat

I used a narrow band Halmeter with a heated sensor, works at idle. When the engine warms up the idle shows lean. It will read lean for a moment when it transitions from pilot jets to main. I use it as a go / no go mixture reading. It's in the first 3 seconds.

+1 for what Kieth said. I don’t remember where I found a write up about this, but it was at least 20 years ago. Possibly on the autox list. I’m not sure it used the wide band sensor after looking @ its wiring & control circuitry on line, plus 5 wires. My sensor has 4 wires. I’ll have to see if there are any markings on it.

Peace,
Pat

Curtis I’m no expert but with many cars and all type of fuel systems I have gotten a fair bit of experience with this as of late.

To your first question regarding static and running, yes you need to adjust for both as the engine and therefore the AFR will not react the same idling or turning at 2500 in your driveway vs WOT under load in 3rd speed.

Which carb you use will determine what you can adjust for and how. MrsBlue has SUs so we adjusted for best cruising AFR most of the adjustment was done running it at 2500 rpm in the driveway , she’s a little rich at idle and leaner then I would like at WOT.

Scarlett has dual PHH40s so adjustments were made after drives to adjust for idling circuit and main circuits separately.

For my Z I use Mikuni HSR carbs , these carbs offers me the flexibility to adjust idle, part throttle and WOT separately so on this one I use the Wideband to adjust each conditions and since the carbs are sensitive to temperature changes it helps me see what’s going on all the time. I’m currently adjusted to 13.5 idle, 14.5 light cruise , 12.5 anything over 1/2 throttle.

Personally after initial adjustments I like to get my cars at full operating temps of all the components so I usually go for a 15m drive before starting.

For recommendations I have AEMs X series in all my cars,
https://www.amazon.ca/AEM-30-0300-Wideb ... B0184TSI84
I like the responsiveness and accuracy and they use a standard Bosh Uego sensor. The gauge is small and easy to place unobtrusively in the car as you can see in the video.

If you want a handheld unit get the Innovate LM-2 dual https://www.innovatemotorsports.com/lm- ... c-kit.html
I have one of these also and it’s very versatile and has full log capabilities and can be easily used on all your cars with a tailpipe adapter

Finally I have found tailpipe reading to always be less accurate and fluctuating then after the headers , I have used the LM2 with both sensors it shows both readings on the screen and tailpipe was always leaner , sometimes by a little often by a lot
Sorry for the long post but hope this helps

(Idle is lean but car was still cold and it was only 45d so normal)
https://i.imgur.com/MOy5wiY.mp4